A Queensland roof takes a serious beating. The subtropical combination of intense UV, heavy summer rainfall, high humidity, and persistent organic matter from trees creates ideal growing conditions for moss, lichen, algae, and black fungal staining on concrete, terracotta, and Zincalume rooflines. Left untreated, biological growth retains moisture against roofing materials, accelerating corrosion on metal, cracking on concrete tiles, and degrading pointing and bedding mortar. The aesthetic impact is obvious; the structural impact is gradual but expensive.
Roof cleaning ranges from a straightforward soft wash (low-pressure chemical application to kill and remove organic growth) through to a full roof restoration, which involves cleaning, repointing and rebedding ridge capping, applying a surface primer, and a weatherproof coating. Soft wash cleaning is appropriate for roofs in good structural condition that have biological growth. Full restoration makes sense when pointing is cracked, tiles are porous or oxidised, or the roof has been neglected for many years.
The critical regulatory consideration in Queensland: any roof restoration work with a total contract value over $3,300 (labour and materials combined) requires the contractor to hold a current QBCC licence. This is a significant and frequently ignored requirement in the roof cleaning industry. Homeowners should request the contractor's QBCC licence number and verify it at qbcc.qld.gov.au before signing any contract for a full restoration. Unlicensed work over $3,300 provides no consumer protection and may void your home insurance in the event of a subsequent claim.